Diamond Colour - Grading Diamond Whiteness
Diamond colour is an indication of the whiteness of a Diamond. A colour scale introduced by the Gemological Institute of America (GIA) attributes a letter of the English alphabet to each grade of whiteness, starting with D colour to denote the absence of all colour.
This photograph shows the reality of how Diamonds varying in whiteness appear in daylight, selecting ten different colour grades for comparison.
Less is More
Less is more applies when considering whiteness. Diamond colour is a measure of how white the stone is. The very whitest Diamonds are assigned the letter "D". Each grade becomes less white as you descend from D colour.
Safe Colour Grades
D colour through to G colour is considered the 'better' colour grades. H colour and I colour Diamonds are sometimes referred to as 'commercial white' and show no tint of colour. From J colour it is possible to see a subtle tint of colour within the Diamond.
Rarely used today are some older references to Diamond colour, such as Jager, River, Top Wesselton, Wesselton, Top Crystal, Crystal, and Cape. Many of these terms arose from the origin of particular Diamonds. such as Cape Diamonds, that was predominant amongst those Diamonds mined out of the Cape of Good Hope. We do still see occasional references to such "old school" terms, but these are seldom used even within the diamond industry itself.
Fluorescence and Whiteness
Remember though, the presence of fluorescence can affect the Diamond colour when viewed from above, often making lower colour Diamonds appear whiter. This is one of the reasons stones are viewed from the side during grading. Ordinarily, strong fluorescence can make a Diamond less valuable resulting in a lower cost, where strong fluorescence reduces brilliance (giving the stone a bluff, or milky hue) However, in some slightly tinted Diamonds, fluorescence can give the effect of whitening the Diamond, which can result in a slightly higher price for the Diamond. If for example, a "J" colour Diamond has a degree of fluorescence that causes it to "face-up" whiter when viewed from above, it would most likely be a little more expensive than the equivalent Diamond, with nil fluorescence.
Natural Fancy Colour
The Diamond whiteness scale does not apply to naturally fancy coloured Diamonds. Diamonds with a noticeably pure colour can vary between pink, blue, green, yellow, orange and brown. Where these occur naturally their rarity makes them very expensive. These noticeable colours are often given the term "fancy coloured". Fancy colour can be attributed to chemical composition, or to structural differences within the Diamond crystal resulting in changes to the way colours of the spectrum are absorbed and reflected.
Diamond colour that is D, E, or F usually demand higher prices because they are much whiter Diamonds. Our advice is very often to choose a Diamond G to I colour or better. This will ensure that your Diamond will be white. Diamonds are generally colour graded by being placed face down and viewed through the side of the stone. This provides the greatest opportunity to view the colour without the distraction of colour, on a white background under white north daylight. Today, many gemologists use a "real daylight" fluorescent tube in a special lamp to work under.
Diamond Colour Samples
Showing Diamond colour comparisons can be difficult between a small range of specific Diamond colours. For this reason, we use a sample set of Diamond colours. Our showroom sample set contains ten colour grades from D through to M. This allows our clients to appreciate the subtle colour changes across several Diamonds. This colour sample set is also available for purchase through our site.